Video / Audio Standards -Codec / Container Part 2
Codec types / characteristics
film
The following codecs have little or no deterioration in image quality. When used for video editing, deterioration of image quality due to encoding is minimized. Also, the load is low both during compression and playback, and we are good at reverse playback. Instead, the amount of data tends to be large.
Motion JPEG Reads as Motion JPEG [Motion Jepeg: MJPEG]. As the name suggests, it is a JPEG compression of each frame of the video. Since JPEG compression deteriorates the image quality to some extent, since there is no compression between frames, the playback and compression load is small, and it is easy to delete frames one by one. It is often used in the recording part of digital cameras.
Lossless compression codec When compressed in this format, there is no deterioration of the video except for the color space. The famous ones are Huffyuv and Lagarith Lossless Video Codec. It is recommended to use it as an intermediate format when you do not want to deteriorate the image quality but want to reduce the capacity, or when editing a video.
The following codecs are formats intended to save and distribute edited and created videos. The data capacity is very small, but it is degraded compared to the original video. Also, because it uses a complicated compression algorithm, it is not suitable for editing work such as joining videos, cutting and inserting. Basically the playback load is high.
H.263 A video format developed for low bit rates. Often used for videophones. If you use DivX, Xivd, etc., it will be in this format. There are many users because the playback load is low compared to other codecs. However, the capacity is a bit large.
H.264 It is a very popular video format today. It is widely used in terrestrial digital broadcasting, mobile phones, next-generation DVD, etc. It is an excellent codec with a high compression rate and little deterioration in image quality. Good for playing low to medium bit rate videos. Instead, the playback load is quite high, so some machine power is required to reproduce it. Encoding a high-capacity video is likely to cause dropped frames. Sometimes called “MPEG-4”.
MPEG-1 Read as MPEG-1 [Mpegwan]. Created by an organization called Moving Picture Experts Group (MPEG). It is used for video CDs. It was a format that was thought to be able to play VHS quality video on CD, but now that VHS has become obsolete and DVDs and BDs have gone mainstream, it has to be said that there is less need to compress in this format. The playback load is low, but the capacity is high.
MPEG-2 This is the mainstream MPEG videos. Since it is good for playing at medium to high bit rates, it is used on DVDs and digital terrestrial broadcasts that require high picture quality. Since it is a lossy compression, the compression rate is high and the data capacity can be reduced. Since the data transfer rate requires 4 to 15 Mbps for both video and audio during playback, it is not suitable for low bit rate video.
Audio
PCM is an uncompressed audio codec that has been around for a long time. It is one of the methods for converting analog data into digital data, which is called pulse code modulation [PCM]. It can be played on most computers. The sound quality is very high, but the capacity is also great. Most of them are in WAV containers by themselves.
LPCM Read as linear PCM. One of the PCM methods, also uncompressed audio. Since there is no lossy compression, this is also very high quality sound. However, the capacity is also large. It is widely used in the audio part of DVD and BD, games for PlayStation 3, etc.
MP2 MPEG audio codec. The extension is “.mp2” or “.mpc”. It is often used as a set with MPEG1 and MPEG2 videos. Some DVDs are recorded in this format. The compression ratio is neither high nor low.
MP3 is an audio codec that has been exploding since 1998. You may have heard of it. The extremely high compression ratio can reduce the amount of data. Also, since compression is done using human auditory psychology, there is little deterioration in sound quality despite the high compression rate. Due to its excellent format, most devices and software support playback. By the way, the official name is “MPEG Audio Layer-3”.
AAC AAC [Advanced Audio Coding] is a standardized format that aims to achieve high sound quality.
